Internet usage has increased dramatically in the past few years and as a result, the usage of hypertext documents that contain hypermedia links has also increased dramatically. Hypermedia links provide an address path to access media content that is related to or associated with text, graphics, video or audio. Typically, a user utilizes a hypermedia link by selecting the link with a mouse. Specifically, the user positions a mouse cursor over the link (which is highlighted or displayed in a color that indicates that it is a link) and clicks the mouse to retrieve media content accessible through the link. Upon the user selection of the link, a web browser program accesses the address path of the media content that is encoded in the link, retrieves the media content and renders the media content to the user. For most wet pages, this entails displaying video information on a video display for a web page. Nevertheless, audio information may also be retrieved and output.
FIG. 1A is a block diagram that illustrates the basic scheme that is employed in retrieving such media content with a conventional web browser 10. The web browser 10 is run on a client computer system 12. The web browser 10 is used to generate a request 14 for the media content from a server computer system 16. Typically, this request 14 is a GET request that complies with the hypertext transfer protocol (HTTP). The server computer 16 receives the request 14, accesses the media content 18 stored therein and returns a copy of the media content 20 to the client computer system 12. The web browser 10 includes code for rendering the media content 20 so that the content is output to the user. Typically, for a web page, the copy of the media content 20 is forwarded as a hypertext markup language (HTML) document. The HTML document may contain a number of hyperlinks that enable the user to gain access to other web sites.
One difficulty encountered with hypertext documents is that the hypermedia links embedded within the documents may be unresolvable (i.e., not resolved to a web set). One of the causes for such unresolvable links is that the storage location of the media 18 may be changed without updating the links contained within the Hypertext document. In such cases, the web browser 10 returns an error message because the media content is no longer located at the address path specified by the link. As a result, the user is unable to access the media content associated with the link.
Similar difficulties may be encountered in different environments. Other references to objects or files may also be subject to change that makes them unresolvable. For example, links and path names that refer to other files or objects may change. These references may also be, for example, object identifiers (object IDs) or other types of signatures that uniquely identify a file or object holding text or other media, such as audio data or video data. FIG. 1B shows the case where an operating system (OS) or network operating system (NOS) 11 at a client 12 seeks access to a resource 13 stored on a server 16. The server 16 may be connected to the client 12 via a local area network (LAN) or wide area network (WAN). The OS/NOS 11 may use an object identifier, path name or other resource identifier to access the resource 13. Unfortunately, such an object identifier, path name or resource identifier may not be current. As a result, access to the resource may not be possible.